Apparatus for paper electrophoresis



INVENTOR li H v 7, 1967 J. HRDINA APPARATUS FOR PAPER ELECTROPHORESIS Feb.

Filed July 31, 1962 1 $3 sw 14, j r\\\\\\\\\\\\\\\\\\\\\\\\\\\ United States Patent O 3,303,120 APPARATUS FOR PAPER ELECTROPHORESXS .iii'l-lirdina, Prague, Czechoslovakia, assignor to Ceskoslovensk akademie vd, Prague, Czechoslovakia, a corporation of Czechoslovakia Filed July 31, 1962, Ser. No. 213,736 Claims priority, application Czechosiovakia, Aug. 7, 1961, 4,849/ 61 8 Claims. (Cl. 204--30tl) The present invention relates to an apparatus for paper electrophoresis. Electrophoretic separation of mixtures of substances on paper with an analytic or preparative objective has become one of the indispensable processes applied in ybiochemical research. The development of applicances for paper electrophoresis has passed through a number of stages. In addition to the most varied appliances produced individually, commercial instruments made by various manufacturers are in use. The existing types of appliances differ from one another mainly by the either substantially horizontal or vertical position of the paper during the electrophoretic process, by a continuous or discontinuous application of the sample on the paper, by the manner of supporting the paper in the apparatus, by the arrangement of the electrodes, in cooled electrophoresis by the manner in which the heat produced in the paper is withdrawn and finally, by the manner of D.C. supply.

It is one of the disadvantages of existing appliances that in spite of a high degree of automation in biochemical laboratories, paper electrophoresis has remained exclusively a matter of manual operation. If a several-hour electrophoretic separation is to be carried out, and the time needed for drying the electrophoretogram is computed, it is frequently necessary to postpone the electrophoretic process until the entire period of time is available.

Another disadvantage of the existing methods of paper electrophoresis lies in the diticulties encountered during removal of the paper after terminated electrophoresis. The wet paper exposed for several hours to a slightly increased temperature, is easily damaged and diicult to fix for drying. If radioactive substances are separated by electrophoresis, a certain risk of contamination is incurred during manipulation with the wet paper.

The present invention aims at removing or mitigating the aforementioned disadvantages of the heretofore known processes and instruments.

The apparatus according to this invention comprises substantially a tank or casing having a removable and at least partially transparent top, within said casing supporting means for the paper strip holding the strip in suspended substantially horizontal position beneath and distanced from said top, two electrode vessels each located laterally of opposing sides of said supporting means and each reciprocable perpendicularly to its longitudinal axis between an operative inner position and an inoperative outer position, and reciprocating means for said electrode vessels causing the same to move simultaneously away from and back to the supporting means between said inner operative positions in which the ends of the paper strip dip into the electrode vessels and said inoperative outer positions in which the ends of the paper strip avoid said electrode vessels to permit excessive liquid to drip oil from the ends of the paper strip before the same is removed rom the casing. The said supporting means may consist of a substantially horizontal plate removably held within the casing and provided with a series of substantially upstanding round-headed pins.

An embodiment of the apparatus according to the invention is shown in the accompanying drawing, wherein idl Patented Feb. 7, 1967 ICC FIG. 1 -represents a longitudinal section taken along the line I-I from FIG. 2 and FIG. 2 is a cross sectional View taken along the line II-II from FIG. l.

The basic arrangement is diagrammatically shown in FIG. 1. A paper 1 is placed horizontally in the working space 2 of the apparatus. The working space comprises a main tank 3 made of a suitable polyvinylchloride plastic whose upper rim is covered by a transparent lid 4. The entire unit may be enclosed in a dismountable sheet-metal casing 5 with a base 6. The paper in the operative space is placed several millimeters below the lid 4 and in its operative position is supported by upstanding pins 7 made of a suitable plastic with rounded tips. The pins are embedded in a horizontal bed plate 8 made also of plastic which is integral with vertical upstanding walls 9, 9', provided with slots 10, 10' which, are engaged by a shaft 11, rotatably mounted in the walls of the tank 3. The entire supporting structure can easily be lifted upwards from its working position after removing the lid 4. During the electrophoretic process the paper 1 reaches with its ends into the electrode vessels 12, 12 as shown in full lines in FIG. 1. These vessels are supplied with electric current from the terminals 19, 19' and transmit the current to the paper strip. They are connected to appropriate slide blocks or other supports 12 which rest slidably on the bottom of the casing 3, and they may be moved upon termination of the electrophoresis from their operative inward position into the inoperative outer position in which outer position the ends of the strip slide from the liquid filled space of vessels 12, 12 over their edges into auxiliary vessels 13, 13 receiving the dripped oil liquid. These auxiliary vessels may be iilled with a liquid absorbing medium such as with blotting paper or the like which will suck olf excessive liquid from the strip. The said displacement of the supports 12" is effected by connecting rods 15, 15 which with one en-d pivot upon pins 14, 14 mounted on a disk fixed on shaft 11. This shaft 11 is rotated in one or the other direction by half revolutions by the motor 17 over the gear box 18. In the shown embodiment the bed plate 8 rests upon vertical side walls 9, Si each of which is provided with a vertical slot 10 fitting over the shaft 11 and permitting the supporting means to be easily removed from the casing 3 after its top 4 has been lifted.

The paper is thus prepared for drying. The drying operation itself is effected by a powerful air stream guided along both sides of the paper in the narrow spaces between the paper and lid 4 and between the paper and plate 8, respectively. The supporting pins 7 do not appreciably interfere with the streaming and drying process. They may be distanced 40 mm. apart and this has proved to be a reasonable compromise between the antagonistic requirements of satisfactory support for the paper and minimum interference with the air stream during drying, as well as with the electrophoresis itself. The distance between the pins can, of course be varied according to requirements.

The air stream is produced by a fan 16 accommodated, along with possibly required other instruments and working members, in a space between the vertical walls of the tank 3 and the outer casing 5. Said fan is driven by a separate motor.

Drying of the paper may be effected in various ways. One of them consists in admitting air from the outside through a lateral opening into the casing or into a channel provided along the rear wall of the tank and hence through a longitudinal slot along the entire length of the working part of the paper into the space above the paper. As, however, theend of the paper on the other side does not reach as far as the front wall of the tank, but is short ci it by about 20 mm., the air stream Iturns at this point towards the underside of the paper, as shown by arrow in FIG. 2. Through the space below the paper the air returns to the backwall and through the longitudinal slot provided therein into a collecting channel, leading to the suction branch of the fan. To ensure a reliable operation of the described arrangement, the longitudinal slot in the rear wall is divided by a partition approximately in the plane of the paper, said partition forming a kind of geometrical continuation of the paper, so as to secure adequate separation of the spaces through which airis admitted Ito the paper and withdrawn therefrom, respectively. If all air flow profiles as well as the volumetric output of the fan are chosen sufficiently large-which can be achieved without difficulty even when a small electric moto'r is used-the minor leaks, no matter whether between paper and the slot partition or elsewhere, do not Iaffect the operation adversely, as long as their profile does not approach the order of magnitude of the flow profiles. Alternatively, the air stream may be guided along the paper by arranging the air admission openings in such a way that the air passes from the front wall of the tank in parallel streams above and below the paper, leaving behind its rear edge through the above described slot in the rear wall into a channel leading to the fan.

Although one form of the invention has been shown and described by way of illustration, it will be understood that it may be constructed in various other embodiments which come within the scope -of the appended claims.

What I claim as my invention is:

1. In a paper strip electrophoresis apparatus the improvement comprising in combination a casing having a removable top; within said casing supporting means for the paper strip holding the strip in suspended substantially horizontal position beneath of and distanced from said top; two electrode vessels each located laterally of opposing sides of said supporting means and each reciprocable perpendicularly to its longitudinal axis between an operative inner position and an inoperative outer position;

ing the same to move simultaneously away from and back to the supporting means between said inner operative position in which the ends of the paper stripdip into the electrode vessels and said inoperative outer position in which the ends of the paper strip avoid said electrode vessels to permit excessive liquid to drip off from the ends of the paper strip before the same is removed from the casing.

2. In a paper strip-electrophoresis apparatus according to claim 1 whereinV said top is atleast partially transparent. Y

3. In a paper strip electrophoresis apparatus according to claim 1 the further improvement comprising an auxiliary vessel associated and displaceable with each electrode vessel and located between the same and said supporting means, said auxiliary vessels mounted and adapted to receive the ends of the paper strip after upon termination of the electrophoretic process the said ends emerged from the electrode vessels, thereby collecting dropped olf liquid.

Vand reciprocating means for said electrode vessels caus- 4l. In a paper strip electrophoresis apparatus according to claim 3 the further improvement comprising a liquid absorbing medium in each auxiliary vessel to suck 01T excessive liquid from the paper strip.

5. In a paper strip electrophoresis apparatus according to claim 1 Ventilating means associated with said casing causing an air stream to pass along and to dry both sides of the paper strip before the same is removed from the casing.

6. In a paper strip electrophoresis apparatus according to claim 1 wherein said supporting means for the paper strip comprises a substantially horizontal bedplate removably held in the casing and a series of substantially regularly spaced upstanding round-headed pins mounted on said plate to support the paper strip.

'7. In a paper strip electrophoresis aparatus according to claim 1 comprising supports for the electrode vessels slidingly resting upon the bottom of the casing, a shaft rotatably mounted in the casing below said supporting plate, and connecting rods loperatively connecting said supports and said shaft to effect a reciprocation of said support. i

8. In a paper strip electrophoresis apparatus according to claim 1 comprising opposite upstanding supporting w-alls for the bedplate, and a Vertical slot in each supporting wall receiving said shaft and permitting said supporting means for the paper strip to be pushed from above over the shaft as well as to be removed from the casing.

References Cited by the Examiner UNITED sTATEs PATENTS 2,768,948 iti/1956 MDna1detai. 204-180 2,834,729 5/1958 Pickeis er a1. 2044-180 2,843,540 7/1958 Y Regner 2044299 2,888,392 5/1959 Grossman etai 204-180 FOREIGN PATENTS 1,057,44o- 3/1954 France. 525,981 12/1955 nary.

OTHER REFERENCES Block et al.: Paper Chromatography and Paper Elec-trophoresis, pages 508-532, 1958.

Canadian Journal of Biochemistry and Physiology, A Rapid Method for Filter Paper Electrophoresis, volume 23, pp. 567-571, 1951. Y

Heftmann: Chromatography, ,Techniq`ues with Various Flow Directions, pp. 134-143, 1961.

Lederer: Chromatographie Reviews, vol. l, pages 146- 151, 1959.

HOWARD S. WILLIAMS, Primary Examiner. JOHN R. SPECK, MURRAY TILLMAN, Examiners.

G. E. BATTIST, E. ZAGARELLA, Assistant Examiners; 

1. IN A PAPER STRIP ELECTROPHORESIS APPARATUS THE IMPROVEMENT COMPRISING IN COMBINATIN A CASING HAVING A REMOVABLE TOP; WITHIN SAID CASING SUPPORTING MEANS FOR THE PAPER STRIP HOLDING THE STRIP IN SUSPENDED SUBSTANTIALLY HORIZONTAL POSITION BENEATH OF AND DISTANCED FROM SAID TOP; TWO ELECTRODE VESSELS EACH LOCATED LATERALLY OF OPPOSING SIDES OF SAID SUPPORTING MEANS AND EACH RECIPROCABLE PERPENDICULARLY TO ITS LONGITUDINAL AXIS BETWEEN AN OPERATIVE INNER POSITION AND AN INOPERATIVE OUTER POSITION; AND RECIPROCATING MEANS FOR SAID ELECTRODE VESSELS CAUSING THE SAME TO MOVE SIMULTANEOUSLY AWAY FROM AND BACK TO THE SUPPORTING MEANS BETWEEN SAID INNER OPERATIVE POSITION IN WHICH THE ENDS OF THE PAPER STRIP DIP INTO THE ELECTRODE VESSELS AND SAID INOPERATIVE OUTER POSITION IN WHICH THE ENDS OF THE PAPER STRIP AVOID SAID ELECTRODE VESSELS TO PERMIT EXCESSIVE LIQUID TO DRIP OFF FROM THE ENDS OF THE PAPER STRIP BEFORE THE SAME IS REMOVED FROM THE CASING. 